Hurricane Sandy–after thrashing the mid-Atlantic Coast, leaving millions without power and submerging large swaths of the New York City waterfront–is inundating wastewater treatment plants nearly 800 kilometers (500 miles) inland.

Jean Chapman, a spokeswoman for the Northeast Ohio Regional Sewer District, which serves roughly 1.2 million customers in the Cleveland area, told Circle of Blue that its Southerly Wastewater Treatment Plant on the Cuyahoga River near Cuyahoga Heights is discharging a “significant amount” of untreated wastewater and stormwater into the river. The exact volume is not known.

National Weather Service

The National Weather Service hydrograph for the Cuyahoga River south of Cleveland shows a flood crest of 20.86 ft Tuesday morning.

The Cuyahoga River at Independence, Ohio, just a few miles upstream from the Southerly plant was almost 1.5 meters (5 feet) above flood stage when it crested late this morning at 6.3 m (20.8 ft).

The sewer district fully or partially treated nearly 5.7 billion liters (1.5 billion gallons) in the last 24 hours at the three facilities it operates–more than triple the daily average.

“Everything is at capacity,” said Chapman.

The most serious risk, however, is diminishing.

Chapman said that the Southerly plant would not be able to treat water at all if the river rose above 7.6 m (25 ft) because of back ups that would occur in the outfall pipe. According to National Weather Service hydrographs, the river has already crested.